In a numerically controlled machine, a plurality of tools are typically carried by a carriage and are brought in a preselected sequence to a work piece to make a specific part. Each individual tool must be cooled and any chip build up must be removed from the part during the machining operation. A solution to this problem included mounting the chip removal and lubricating device on a fixed wall or structure adjacent the spindle of the machine. In this manner, the relative position of the work piece with respect to the device is always fixed, regardless of the position of the machine carriage. However, the chip and lubricating device so positioned may obscure an operator's field of view when inspecting the part, thereby necessitating the frequent moving of the device in order to clear his field of view. There is therefore a need for a chip removal and tool lubricating device wherein the relative position of the device with the tool and the part being machined remains substantially constant without unduly obstructing the view of the operator.
A machine tool designed for extremely accurate machining operations must compensate for errors resulting from thermal growth of the machine components. Screw-nut drives are generally used in machine tools such as a Lathe and the like and are used to accurately position a work piece supporting member or a tool. During operation of the machine tool, the resultant heat produced causes the lead screw to expand, thereby introducing errors into the system. In a situation where both ends of the lead screw are fixed, the thermal expansion will cause the screw to sag or buckle up, fooling the positioning system of the machine that tracks the number of rotations of the screw to determine the position of the carriage. Additionally, stresses are introduced at each end of the screw that could cause premature failure of the screw. There is therefore a need to provide a screw-nut drive that is compensated for the expected thermal growth of the lead screw during normal operations.
In a machine tool with a movable carriage or table, the movement of the table is typically accomplished on accurately machined close tolerance guideways and bearing assemblies. A numerically controlled machine is programmed by its operator to provide specific machining operations for a specific part. After programming, the machine then goes through its various paces automatically, without any intervention from the operator. If the operator had made a mistake in programming, the machine could conceivably crash, where the cutting tool or the movable carriage may jam into the part being machined or into the machine spindle, generating large shock forces that could damage the highly machined guideways. When a crash occurs, the machine is inspected for damages. Typically, the guideways will have indentations from the bearings, requiring rebuilding or replacement. The machine is then taken out of production while it is being repaired, thereby causing revenue loss. There is therefore a need to provide shock resistant guideways that will be able to absorb the shock forces during a crash without any damage, thereby avoiding an expensive downtime.